Is there a limit to the number of life insurance policies one can buy? If not, can my nominee claim all the policies in the event that something unfortunate happens to me?
There is no limit to the number of policies, but most insurers follow underwriting guidelines that restrict the total sum assured, depending on your age and annual income, to avoid anti-selection. Therefore, it is important to disclose details of earlier policies and annual income, when applying for a new policy.

In case of a claim, the proceeds under the policies will be paid to the nominee(s).

I am 23 and have started work as a deep sea diver. Should I buy a life cover or wait for some time?
It is advisable to buy a life cover at a younger age. With lesser health risks, the insurers would offer a high cover at low cost. However, since deep sea diving is risk-based, the insurers would determine the risk profile on the basis of the locations you dive, work frequency, etc. The premium may be loaded, or in some cases, the cover may get rejected on the basis of the risk profile.

Do insurers pay if murdered?
The basic death cover in a policy is payable in case of death and, hence, murder too. However, if an accidental disability benefit rider is taken, it needs to be proved the assured was not involved in criminal activity, and the cause for murder was not linked to this.

I am 43, working in a PSU. I have not bought a pension plan. I will retire at 58, and need Rs 15,000 monthly to meet expenses then. Which pension scheme should I buy?
To receive pension 15 years hence, create a corpus by investing in a deferred annuity plan, or any other that matures in 15 years. Then purchase an immediate annuity out of this sum, which would meet the pension needs. The amount to be received will depend on the corpus size, the then prevailing annuity rates (interest rates) and the type of pension you opt for. You can use retirement calculators available with insurers to estimate the corpus, for a desired pension. It is important to factor in inflation while estimating.